Expandable chair assembly

ABSTRACT

A chair assembly has a seat, a backrest and an expandable leg supporting device. The seat has a front end and a rear end. The backrest is connected to the rear end of the seat. The expandable leg supporting device is mounted on the front end of the seat and has a base, at least one extension frame and a frame driving device. The base is mounted securely on the front end of the seat. The least one extension frame is connected to the base. The frame driving device is mounted on the base and is connected to the at least one extension frame to pivot the at least one extension frame relative to the base. Accordingly, the chair assembly can be expanded to support legs of a user in an expanded condition.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a chair, and more particularly to anexpandable chair assembly to support legs of a user in an expandedcondition.

2. Description of Related Art

Chairs enable person sitting thereon to support the weights of thesitter. A chair substantially comprises a seat and a backrest forsupport the back of a sitter. The backrest may be adjustable in anglerelative to the seat to fit with different needs of different sitters.

However, when a person sits on a chair for a long time, for example in along vehicle traveling, the legs of the sitter on the convention chairwill become tired, numb or pained due to long term of bending.Accordingly, the conventional chair should be further improved toprovide an enhanced comforting effect.

To overcome the shortcomings, the present invention tends to provide anextendable chair assembly to mitigate or obviate the aforementionedproblems.

SUMMARY OF THE INVENTION

The main objective of the invention is to provide an expandable chairassembly to support legs of a user in an expanded condition. The chairassembly has a seat, a backrest and an expandable leg supporting device.The seat has a front end and a rear end. The backrest is connected tothe rear end of the seat. The expandable leg supporting device ismounted on the front end of the seat and has a base, at least oneextension frame and a frame driving device. The base is mounted securelyon the front end of the seat. The least one extension frame is connectedto the base. The frame driving device is mounted on the base and isconnected to the at least one extension frame to pivot the at least oneextension frame relative to the base.

Other objects, advantages and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an extendable chair assembly inaccordance with the present invention;

FIG. 2 is a perspective view of the expandable leg supporting device ofthe chair assembly in FIG. 1 in an expanded condition;

FIG. 3 is an enlarged perspective view of the frame driving device ofthe chair assembly in FIG. 1;

FIG. 4 is a partial perspective view of the expandable leg supportingdevice in FIG. 1;

FIG. 5 is an enlarged perspective view of the panel driving device ofthe chair assembly in FIG. 1;

FIG. 6 is an enlarged perspective view of the detecting device of thechair assembly in FIG. 1;

FIG. 7 is an operational side view of the expandable leg supportingdevice of the chair assembly in FIG. 1; and

FIG. 8 is a side view of the expandable leg supporting device of thechair assembly in FIG. 1 in an expanded condition.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

With reference to FIGS. 1 and 2, an extendable chair assembly inaccordance with the present invention comprises a seat 10, a backrest 20and an expandable leg supporting device 30. The seat 10 has a front endand a rear end. The backrest 20 is connected to the rear end of the seat10.

The expandable leg supporting device 30 is mounted on the front end ofthe seat 10 and comprises a base 31, at least one extension frame33,33A,33B and a frame driving device 32. The base 31 is mountedsecurely on the front end of the seat 10. The at least one extensionframe 33,33A,33B is connected to the base 31. Preferably, threeextension frames 33,33A,33B are implemented, are telescopicallyconnected with each other and include an outer extension frame 33, amiddle extension frame 33A and an inner extension frame 33B arrangedfrom outside to inside in sequence. Each extension frame 33,33A,33B hasa volume gradually increasing from the inner extension frame 33B to theouter extension frame 33, such that a smaller extension frame 33A,33B ismounted in a large extension frame 33,33A. In addition, each extensionframe 33,33A,33B has two side panels 332,332A,332B, a rear panel331,331A,331B and an opened front panel. Each side panel 332,332A,332Bhas an inner surface facing to each other and an outer surface oppositeto each other. The rear panel 331 of the outer extension frame 33 isconnected pivotally to the base 31.

The frame driving device 32 is mounted on the base 31 and is connectedto the at least one extension frame 33,33A,33B to pivot the at least oneextension frame 33,33A,33B relative to the base 31. With furtherreference to FIG. 3, the frame driving device 32 comprises a drivingmotor 321, a worn rod 322, a worn gear 323, a pinion 324, a driving gear325 and a pivotal rod 326. The driving motor 321 is mounted securely onthe base 31. The worn rod 322 is connected to and driven by the drivingmotor 321. The worn gear 323 engages and is driven by the worn rod 322.The pinion 324 is co-axially mounted on the worn gear 323. The drivinggear 325 engages the pinion 324. The pivotal rod 326 is co-axiallymounted on and protrudes from the driving gear 325, is connectedsecurely to the at least one extension frame 33,33A,33B and ispreferably connected securely with the rear panel 331 of the outerextension frame 33.

With further reference to FIG. 4, the outer extension frame 33 has amiddle extension driving device 333 comprising a middle motor 334, amiddle threaded rod 335 and a middle nut 336. The middle motor 334 ismounted securely on the rear panel 331 of the outer extension frame 33.The middle threaded rod 335 is connected to and driven by the middlemotor 334. The middle nut 336 is mounted rotatably around the middlethreaded rod 335 and is connected securely to the rear panel 331A of themiddle extension frame 33A.

The middle extension frame 33A has an inner extension driving device333A comprises an inner motor 334A, an inner threaded rod 335A and aninner nut 336A. The inner motor 334A is mounted securely on the rearpanel 331A of the middle extension frame 33A. The inner threaded rod335A is connected to and driven by the inner motor 334A. The inner nut336A is mounted rotatably around the inner threaded rod 335A and isconnected securely to the rear panel 331B of the inner extension frame33B.

In addition, the outer extension frame 33 has two rails 337 mountedrespectively on the inner surfaces of the side panels 332. The middleextension frame 33A has two sliders 338A and two rails 337A. The sliders338A are mounted respectively on the outer surfaces of the side panels332A of the middle extension frame 33A and are slidably connected withthe rails 337 on the outer extension frame 33. The rails 338A aremounted respectively on the inner surfaces of the side panels 332A ofthe middle extension frame 33A. The inner extension frame 33B has twosliders 338B mounted respectively on the outer surfaces of the sidepanels 332B of the inner extension frame 33B and slidably connected withthe rails 337A on the middle extension frame 33A.

With further reference to FIG. 5, the expandable leg supporting device30 further has a foot supporting panel 34 pivotally connected to theinner extension frame 33B. A panel driving device 333B is mounted on theinner extension frame 33B, is connected to the foot supporting panel 34and has a panel driving motor 334B, a driving pulley 3341B, a drivenpulley 335B, a belt 336B and a pivotal axle 3351B. The panel drivingmotor 334B is mounted on the rear panel 331B of the inner extensionframe 33B. The driving pulley 3341B is connected to and driven by thepanel driving motor 334B. The driven pulley 335B is mounted rotatably onthe inner extension frame 33B. The belt 336B is mounted endlessly aroundthe driving pulley 3341B and the driven pulley 335B. The pivotal axle3351B is co-axially formed on and protrudes from the driven pulley 335B.In addition, the foot supporting panel 34 has two ends and two pivotalears 341 formed respectively on the ends of the foot supporting panel34. One of the pivotal ears 341 is connected securely with the pivotalaxle 3341B of the panel driving device 333B, and the other pivotal ear341 is connected pivotally to the rear panel 331B of the inner extensionframe 33B with a pivot.

With reference to FIGS. 4 and 6, the expandable leg supporting device 30further has a middle detecting device 40 mounted between the outerextension frame 33 and the middle extension frame 33A and comprises apotentiometer 41, a detecting gear 411, a rod mount 42, a rotatable rod421, two end gears 422,422A and a rack 43. The potentiometer 41 ismounted on one of the side panels 332A of the middle extension frame33A. The detecting gear 411 is mounted on and connected to thepotentiometer 41. The rod mount 42 is mounted securely on the side panel332A of the middle extension frame 33A. The rotatable rod 421 is mountedrotatably on the rod mount 42 and has two ends respectively protrudingout from two sides of the rod mount 42. The end gears 422,422A include afirst end gear 442 and a second end gear 422A and are mountedrespectively on the ends of the rotatable rod 421. The first end gear422 engages the detecting gear 411. The rack 43 is mounted securely onthe outer extension frame 33 and engages the second end gear 422A.

In addition, an inner detecting device may be mounted between the middleextension frame 33A and the inner extension frame 33B and may have thesame components as that of the middle detecting device 40.

To expand the leg supporting device 30, with reference to FIGS. 2 and 7,the driving motor 321 is switched on and drives the worn rod 322 torotate, and the outer extension frame 33 can be pivoted relative to thebase 31 with the transmission of the worn gear 323, the pinion 324, thedriving gear 325 and the pivotal rod 326.

With reference to FIG. 4, when the middle motor 334 is switched on, themiddle threaded rod 335 is rotated and the middle nut 336 is moved alongthe middle threaded rod 335 with the threaded engagement between themiddle threaded rod 335 and the middle nut 336. Accordingly, the middleextension frame 33A will be moved to extend out of the outer extensionframe 33. In addition, with the arrangement of the rails 337 and thesliders 338A between the outer and middle extension frames 33,33A, themovement of the middle extension frame 33A is smooth.

Similarly, with reference to FIG. 2, when the inner motor 334A isswitched on, the inner threaded rod 335A is rotated and the inner nut336A is moved along the inner threaded rod 335A with the threadedengagement between the inner threaded rod 335A and the inner nut 336A.Accordingly, the inner extension frame 33B will be moved to extend outof the middle extension frame 33A. With the arrangement of the rails337A and the sliders 338B between the middle and inner extension frames33A,33B, the movement of the inner extension frame 33B is smooth.Accordingly, the extension frames 33,33A,33B of the leg supportingdevice 30 can be expanded to support the legs of a sitter in an expandedcondition.

With reference to FIG. 5, when the panel driving motor 334B is switchedon, the foot supporting panel 34 can be pivoted relative to the innerextension frame 33B with the transmission of the driving pulley 3341B,the belt 336B, the driven pulley 335B and the pivotal axle 3351B.Accordingly, the feet of the sitter can step onto the foot supportingpanel 34.

With reference to FIG. 6, when the middle extension frame 33A is movedto extend out of the outer extension frame 33, the rod mount 42 willmove with the middle extension frame 33A. Consequently, the rotatablerod 421 with the end gears 422,422A will be rotated due to theengagement between the rack 43 and the second end gear 422A, and thedetecting gear 411 is also rotated. Accordingly, the potentiometer 41will be rotated to change the electric resistance of the potentiometer41. With the change of the electric resistance of the potentiometer 41,the position of the middle extension frame 33A out of the outerextension frame 33 can be detected. The operation of the inner detectingdevice is the same as that of the middle detecting device 40 and isomitted.

With reference to FIGS. 7 and 8, when the outer extension frame 33 ispivoted relative to the base 31 to a horizontal level and the extensionframes 33,33A,33B are expanded from each other, the legs of a sittersitting on the chair assembly can be put and supported on the expandedextension frames 33,33A,33B and the feet of the sitter can step on thefoot supporting panel 34. Accordingly, the legs of the sitter can becompletely expanded and excellently supported, such that the comfortingeffect provided by the chair assembly is enhanced and can be kept for along time. In addition, the space for arranging and storing the foldableleg supporting device 30 can be reduced while the leg supporting device30 is not in use.

Even though numerous characteristics and advantages of the presentinvention have been set forth in the foregoing description, togetherwith details of the structure and function of the invention, thedisclosure is illustrative only, and changes may be made in detail,especially in matters of shape, size, and arrangement of parts withinthe principles of the invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed.

1. A chair assembly comprising: a seat having a front end and a rearend; a backrest connected to the rear end of the seat; and an expandableleg supporting device mounted on the front end of the seat andcomprising a base mounted securely on the front end of the seat; atleast one extension frame connected to the base; and a frame drivingdevice mounted on the base and connected to the at least one extensionframe to pivot the at least one extension frame relative to the base. 2.The chair assembly as claimed in claim 1, wherein the frame drivingdevice comprises a driving motor; a worn rod connected to and driven bythe driving motor; a worn gear engaging and driven by the worn rod; apinion co-axially mounted on the worn gear; a driving gear engaging thepinion; and a pivotal rod co-axially mounted on and protruding from thedriving gear and connected securely to the at least one extension frame.3. The chair assembly as claimed in claim 2, wherein the expandable legsupporting device has three extension frames telescopically connectedwith each other and including an outer extension frame, a middleextension frame and an inner extension frame arranged from outside toinside in sequence; each extension frame has a volume graduallyincreasing from the inner extension frame to the outer extension frame;and the outer extension frame is connected securely with the pivotal rodof the frame driving device.
 4. The chair assembly as claimed in claim3, wherein the outer extension frame has a middle extension drivingdevice comprising a middle motor mounted securely on the outer extensionframe; a middle threaded rod connected to and driven by the middlemotor; and a middle nut mounted rotatably around the middle threaded rodand connected securely to the middle extension frame; and the middleextension frame has an inner extension driving device comprising aninner motor mounted securely on the middle extension frame; an innerthreaded rod connected to and driven by the inner motor; and an innernut mounted rotatably around the inner threaded rod and connectedsecurely to the inner extension frame.
 5. The chair assembly as claimedin claim 3, wherein the outer extension frame has two side panels eachhaving an inner surface facing to each other; and two rails mountedrespectively on the inner surfaces of the side panels; the middleextension frame has two side panels each having an inner surface facingto each other and an outer surface opposite to each other; two slidersmounted respectively on the outer surfaces of the side panels of themiddle extension frame and slidably connected with the rails on theouter extension frame; two rails mounted respectively on the innersurfaces of the side panels of the middle extension frame; and the innerextension frame has two side panels each having an outer surfaceopposite to each other; two sliders mounted respectively on the outersurfaces of the side panels of the inner extension frame and slidablyconnected with the rails on the middle extension frame.
 6. The chairassembly as claimed in claim 5, wherein the expandable leg supportingdevice further has a foot supporting panel pivotally connected to theinner extension frame.
 7. The chair assembly as claimed in claim 6,wherein the inner extension frame further has a panel driving devicemounted on the inner extension frame, connected to the foot supportingpanel and having a panel driving motor mounted on the inner extensionframe; a driving pulley connected to and driven by the panel drivingmotor; a driven pulley mounted rotatably on the inner extension frame; abelt mounted endlessly around the driving pulley and the driven pulley;and a pivotal axle co-axially formed on and protruding from the drivenpulley; and the foot supporting panel has two ends and two pivotal earsformed respectively on the ends of the foot supporting panel, whereinone of the pivotal ears is connected securely with the pivotal axle ofthe panel driving device and the other pivotal ear is connectedpivotally to the inner extension frame with a pivot.
 8. The chairassembly as claimed in claim 7, wherein the expandable leg supportingdevice further has a middle detecting device mounted between the outerextension frame and the middle extension frame and comprising apotentiometer mounted on the middle extension frame; a detecting gearconnected to the potentiometer; a rod mount mounted securely on themiddle extension frame; a rotatable rod mounted rotatably on the rodmount and having two ends respectively protruding out from two sides ofthe rod mount; a first end gear and a second end gear mountedrespectively on the ends of the rotatable rod, wherein the first endgear engages the detecting gear; and a rack mounted securely on theouter extension frame and engaging the second end gear.
 9. The chairassembly as claimed in claim 8, wherein the expandable leg supportingdevice further has an inner detecting device mounted between the middleextension frame and the inner extension frame and has a same componentsas that of the middle detecting device.
 10. The chair assembly asclaimed in claim 4, wherein the outer extension frame has two sidepanels each having an inner surface facing to each other; and two railsmounted respectively on the inner surfaces of the side panels; themiddle extension frame has two side panels each having an inner surfacefacing to each other and an outer surface opposite to each other; twosliders mounted respectively on the outer surfaces of the side panels ofthe middle extension frame and slidably connected with the rails on theouter extension frame; two rails mounted respectively on the innersurfaces of the side panels of the middle extension frame; and the innerextension frame has two side panels each having an outer surfaceopposite to each other; two sliders mounted respectively on the outersurfaces of the side panels of the inner extension frame and slidablyconnected with the rails on the middle extension frame.
 11. The chairassembly as claimed in claim 10, wherein the expandable leg supportingdevice further has a foot supporting panel pivotally connected to theinner extension frame.
 12. The chair assembly as claimed in claim 11,wherein the inner extension frame further has a panel driving devicemounted on the inner extension frame, connected to the foot supportingpanel and having a panel driving motor mounted on the inner extensionframe; a driving pulley connected to and driven by the panel drivingmotor; a driven pulley mounted rotatably on the inner extension frame; abelt mounted endlessly around the driving pulley and the driven pulley;and a pivotal axle co-axially formed on and protruding from the drivenpulley; and the foot supporting panel has two ends and two pivotal earsformed respectively on the ends of the foot supporting panel, whereinone of the pivotal ears is connected securely with the pivotal axle ofthe panel driving device and the other pivotal ear is connectedpivotally to the inner extension frame with a pivot.
 13. The chairassembly as claimed in claim 12, wherein the expandable leg supportingdevice further has a middle detecting device mounted between the outerextension frame and the middle extension frame and comprising apotentiometer mounted on the middle extension frame; a detecting gearconnected to the potentiometer; a rod mount mounted securely on themiddle extension frame; a rotatable rod mounted rotatably on the rodmount and having two ends respectively protruding out from two sides ofthe rod mount; a first end gear and a second end gear mountedrespectively on the ends of the rotatable rod, wherein the first endgear engages the detecting gear; and a rack mounted securely on theouter extension frame and engaging the second end gear.
 14. The chairassembly as claimed in claim 13, wherein the expandable leg supportingdevice further has an inner detecting device mounted between the middleextension frame and the inner extension frame and has a same componentsas that of the middle detecting device.
 15. The chair assembly asclaimed in claim 3, wherein the expandable leg supporting device furtherhas a foot supporting panel pivotally connected to the inner extensionframe.
 16. The chair assembly as claimed in claim 15, wherein the innerextension frame further has a panel driving device mounted on the innerextension frame, connected to the foot supporting panel and having apanel driving motor mounted on the inner extension frame; a drivingpulley connected to and driven by the panel driving motor; a drivenpulley mounted rotatably on the inner extension frame; a belt mountedendlessly around the driving pulley and the driven pulley; and a pivotalaxle co-axially formed on and protruding from the driven pulley; and thefoot supporting panel has two ends and two pivotal ears formedrespectively on the ends of the foot supporting panel, wherein one ofthe pivotal ears is connected securely with the pivotal axle of thepanel driving device and the other pivotal ear is connected pivotally tothe inner extension frame with a pivot.
 17. The chair assembly asclaimed in claim 16, wherein the expandable leg supporting devicefurther has a middle detecting device mounted between the outerextension frame and the middle extension frame and comprising apotentiometer mounted on the middle extension frame; a detecting gearconnected to the potentiometer; a rod mount mounted securely on themiddle extension frame; a rotatable rod mounted rotatably on the rodmount and having two ends respectively protruding out from two sides ofthe rod mount; a first end gear and a second end gear mountedrespectively on the ends of the rotatable rod, wherein the first endgear engages the detecting gear; and a rack mounted securely on theouter extension frame and engaging the second end gear.
 18. The chairassembly as claimed in claim 17, wherein the expandable leg supportingdevice further has an inner detecting device mounted between the middleextension frame and the inner extension frame and has a same componentsas that of the middle detecting device.
 19. The chair assembly asclaimed in claim 3, wherein the expandable leg supporting device furtherhas a middle detecting device mounted between the outer extension frameand the middle extension frame and comprising a potentiometer mounted onthe middle extension frame; a detecting gear connected to thepotentiometer; a rod mount mounted securely on the middle extensionframe; a rotatable rod mounted rotatably on the rod mount and having twoends respectively protruding out from two sides of the rod mount; afirst end gear and a second end gear mounted respectively on the ends ofthe rotatable rod, wherein the first end gear engages the detectinggear; and a rack mounted securely on the outer extension frame andengaging the second end gear.
 20. The chair assembly as claimed in claim3, wherein the expandable leg supporting device further has an innerdetecting device mounted between the middle extension frame and theinner extension frame.